肩関節屈曲運動時に作用する筋力の数値解析

抄録

Observing the human upper limb from the point of view of mechanics, every degree of freedom of motion is actuated and controlled by more than two muscles. Many biomechanical researchers have investigated the principles of the complex workings of human muscles using a mechanomathematical model, to obtain more knowledge about the musculoskeletal system control. In this paper we describe a method of numerical analysis of muscle force in a human upper limb during flexion of the shoulder joint. Because no muscle force can be calculated from only the equilibrium equations of force or moment, the optimization method using Lagrange multipliers was applied to this analysis. Muscles were modeled by a straight line from the origin to the insertion. Parameters in the object function were selected to express the muscle properties acting only in the direction of the contraction. Therefore, the synergist and the antagonist could be separated analytically. Moreover, the distribution of muscle force in the wide area of the muscle-bone adhesion depends on shoulder joint angle. Therefore, the muscle-bone adhesive point was also determined to minimize the objective function. The results obtained from this analysis were confirmed by experiments using electromyography.